John a



(No Model.)

J. A. MGGREGOR.

HUISTING MAUHINB.

Patented 1360.29, 1896.

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UNITED STATES ATENT OFFICE.

JOHN A. MCGREGOR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE EDWINI-IARRINGTON, SON ab COMPANY, INCORPORATED, OFV

SAME PLACE.

HolsTINc-MACHINE.

SPECIFICATION forming part of Letters Patent No. 573,904, dated December29, 1896.. Application filed December l, 1893. Serial No. 492,427. (Nomodel.)

To all whom, t may concern:

Be it known that I, JOHN A. MCGEEGOR, of the city and county ofPhiladelphia and State of Pennsylvania, have invented an Improvement inHoisting-Machines, of which the following is a specification.

My inventionfrelates to hoisting-machin es; and it consists of certainimprovements which are fully set forth in the following specificationand shown in the accompanying drawings, which form a part thereof.

My invention comprehends certain improvements in so constructing thehoist that a different degree of friction may be created to increase ordecrease the tendency of the hoist to run down. vThese variousimprovements will be better understood by reference to the accompanyingdrawings, in which- Figure l is a side sectional elevation of myimproved hoisting-machine, and Fig. 2 is a transverse section of same.

Ais the main frame and has j ournaled within it a transverse shaft B,having secured or formed integral thereon theWorm-wheel O,

which is preferably inclosed within the case A.

D is a worm meshing with the worm-Wheel O and is secured to or formedintegral with the shaft E, which is journaled within the frame A atright angles to the shaft B and contains upon its outer or free end ahandchain wheel K, the chain of whicht is adapted to be operated by handin the usual inanner in operating the hoist and is guided throughsuitable guides K', secured to the frame A. The rear bearing of theshaft E is enlarged, as at c, so that if permitted to work against theface F of the frame A it will create a considerable friction owing tothe large surface contact. When but asmall frictional contact isrequired, such as in cases where it is desired to make the lifting orpower chain L with its lifting-hook run down freely, a

small bearing G, carried in the frame A, may be forced forward by meansof a screw H, so as to push the bearing G away from the rear face F, as-indicated in Fig. l, and thereby reduce the extent of surface infrictional contact. The screw I-I may be providedwith a chain-wheel I,over which a light handchain wheel J may pass, so as to be able tochange the frictional contact when the hoist is in an elevated position.To enable the part c to come into contact with the face or bearing F,clearance must be provided to permit the shaft E to move longitudinallyin its bearing. The tendency of the worm D Vworking in the worm-wheel Ois to force the shaft E backward against its thrust-bearing, and it istherefore evident that by varying the extent of frictional contact itsthrustbearing may prevent to the desired degree the weight of thelifting-chain L and its hook, causing the machine to run down. It isalso evident that under such conditions the hoist may be brought intosuch adjustment that a very slight movement of the hand-chain 7a willcause the machine to run down fast or Slowly.

M M are two lifting-chain wheels over which thelift-chains L L pass andare provided with square or substantially square holes, as at m, whichfit upon square or substantially square ends b of the shaft B, carryingthe worm- Wheel O. The shaft B is provided With shoulders adjacent tothe frame A, between which and the outer washers r the chain-wheels Mare clamped through the agency of a transverse bolt R. In this mannerthe chainwheels are easily attached to the shaft B1 and yet are readilyremoved for repairs, and no amount of weight upon the chain L can turnthe said chain-wheels M upon the said shaft B. There should be nomaterial frictional contact between the bearing A of the frame A and thechain wheels M, but the said wheels should be carried upon the shaft Bin such a manner as to prevent any possibility of the turningindependently of the shaft.

The hoist as an entirety may be suspended by means of a hook O, pivotedto a frame P, secured to the frame A by being sleeved upon its bearingsA concentrically with the `hollow transverse shaft B.

While I prefer the construction shown, I do not limit myself to theminor details thereof, as they may be modified without departing fromthe principles of my invention.`

VVhatI claim as new,'and desire to secure by Letters Patent, is

In a hoisting-machine, the combination of the :main frame formed with abearing-socket F of enlarged diameter adjacent to the thrust IOO end ofthe Worm-shaft, a Worin-shaft journaled in said frame and having ajournal e of enlarged diameter journaled in the enlarged bearing-sooketF and free to be moved longitudinally therein so as to bring the faee ofthe journal e of enlarged diameter into frietional Contact With the faceof the bearing-socket., or to he moved out of Contact therewith, and anadj usting-sorew H passing through the end of the socket and hearing onthe face of the journal e, for moving the Worm-shaft and causing theface of the journal to make frietional Contact With the face of the`socket, or not to make Contact there- With, whereby a slow or despatchmovement may be imparted to the hoist by the resulting application orremoval of friet-ion to the Worin-shaft..

In testimony of which invention I have hereunto set my hand.

' JOHN A. MCGREGOR. Vitnesses:

ERNEST HOWARD HUNTER, HELEN L. MOTHERWELL.

